Hi @nitin-godhani,
Thanks a lot for reaching out to us.
Looking at your code everything should work just fine. However, you will need to ensure that the global $post_id variable in use the correct one from your post/page.
It is important that you make sure that your code is within the WP Loop, otherwise, you will need to provide a second parameter on the functions for the post id.
Kindly check out the following samples that might be able to help you out.
https://www.advancedcustomfields.com/resources/repeater/
Let me know how it goes.
